As Nick Matzke pointed out in a comment on the last of these, there are other creationist organizations out there of some significance, such as the Foundation for Thought and Ethics (publisher of the creationist/intelligent design textbook, Of Pandas and People), Probe Ministries (Ray Bohlin's group in Texas which authored the annotated bibliography of Josh McDowell's book Reasons Skeptics Should Consider Christianity--the anti-evolution sections of which were ghost authored by an individual who now supports evolution), and Hugh Ross's old-earth creationist group, Reasons To Believe. There are also five groups that were listed in Cole's article which I did not cover--these were the five smallest groups, the Creation Education Society of Tennessee, the Creation Resource Foundation of El Dorado, California, the Creation Science Association for Mid-America of Kansas City, Missouri (originators of the "Lucy's knee joint" argument), the Creation-Science Fellowship of Pittsburgh, and the Genesis Institute of Mead, Washington. And there are still others out there, like the Twin Cities Creation Science Association of Minneapolis/St. Paul, Kent Hovind's organization (which didn't file anything with the IRS, which is part of why he's in jail right now), and various online creationist ministries.

I may, as Nick suggested, take a look at some of these others in the future.

At this point, however, I wanted to see if any conclusions can be drawn from the data in the Form 990s of the groups I've covered so far. I took a look at one section of each of the Form 990s which gives income data for previous years, and totaled those amounts up for each year across all the groups for which I had data. In some cases, I had to use other sources which were not quite comparable (such as the revenue figures from John Cole's article), but are probably good enough for approximation to look at the size of the creationist market each year. (The main difference between the income figures I used versus the revenue figures is that the income figures show money coming in for purchases without subtracting the cost of goods sold, while the revenue numbers deduct the cost of goods sold.) The Discovery Institute's totals were used, even though the DI does more than creationism, so that may have contributed to an overestimate, while the omission of all of the other groups above would have contributed to an underestimate. Since the DI brings in considerably more revenue than the other groups, it would take quite a few creationist groups making less than $100,000 a year to make up the difference. So this can't be considered definitive.

Given this total size of the creationist market for each year, I then looked at each group's percentage of that marketplace, and how it has changed over time. Here are the numbers, rounded to the closest $1 million:

Even with these approximations and limitations, there are a few things that stand out clearly:

1. The marketplace for creationism has been growing.2. Answers in Genesis' market share has grown and dominates the market.3. The Institute for Creation Research has had a declining market share.4. The Discovery Institute's Center for Science and Culture has had a fairly static market share (overrepresented here, as well, since their numbers include other branches of the DI).5. Other creationist groups have tended to lose market share in the face of Answers in Genesis's dominance, even if their overall revenue has grown.